The present invention relates to a roller heating system for a lamination machine and a process for producing the rolling shaft thereof, more particularly, to a rubber rolling shaft with electric heating wires, which can simplify the heating structures of the lamination machine and shorten the preheating time required for the laminating machine.
In the past, various sizes of files were required to keep important documents such as papers and letters, etc. However, these valuable documentary papers or vouchers are almost paper products and thus are liable to be ruined after repeated utilization and damage of vapor and smuts, etc. in the environment. Moreover, memorable photographs are frequently touched or repeatedly taken out from photo albums, and thus the quality of the photo pictures suffers deterioration.
In order to prevent these documents from damage caused by natural or man-made factors, a general method for protecting/maintaining these documents is to laminate a layer of plastic film onto the paper documents with the employment of a laminating machine. The layer of laminating plastic film, usually made of a transparent plastic material, not only provides protection for these paper products from water and dirt, but also avoids wear and tear in use so that the photographs, certificates and so on can be properly preserved.
Please refer to FIG. 1, which is a schematic diagram of the construction of a laminating machine in the prior art. The conventional laminating machine mainly includes a heating device 10 and a pair of rollers 11, wherein the heating device 10 is constructed by mounting a pair of electrical heaters 13 respectively in a recess 15 of a set of thin aluminum plate means 12 and constraining the electrical heaters 13 respectively in the recess 15 by a pair of press plates 14.
Referring to FIG. 2, which is a schematic working diagram of the conventional laminating machine, when the conventional laminating machine proceeds with pressurizing lamination of a desired article 20 by the pair of rollers 11, the set of thin aluminum plate means 12 are preheated by the pair of electrical heaters 13. After the set of thin aluminum plate means 12 are heated to a working temperature, the top and bottom surfaces of the desired article 20 are respectively covered with one layer of laminating plastic film 21 and are fed to the heating device 10 in a direction 22 to be heated. During heating, the fusion gum of the inner surface of the laminating plastic film 21 become molten and viscous, and the article 20 covered with the layers of the laminating plastic film 21 is then immediately fed in between the pair of rollers 11. The laminating plastic films 21 are compressed by the set of rollers 11 to bond onto the article 20.
However, such a laminating machine needs a longer preheating time because the set of thin aluminum plate means 12 are required to be firstly preheated to the working temperature before lamination; otherwise the fusion gum of the inner surface of the laminating plastic film 21 would not get molten and viscous, and then the laminating plastic film 21 is unable to adhere onto the article desired for lamination. Furthermore, such a laminating machine is incapable of controlling its ambient temperature since the laminating plastic film 21 after heated is transmitted through a travel distance out of the set of thin aluminum plate means 12, and then arrives to the set of rollers 11 for lamination. Within this travel distance, the ambient temperature would affect the adhesion state of the laminating plastic film 2. If the ambient temperature in the vicinity of the heating device 10 is much higher, it leads to early cohesion of part of the laminating plastic film 21 onto the article before the compression of the set of rollers 11. Blisters would form or ruggedness would produce between the laminating plastic film 21 and the surface of such a laminated document, photo and so forth. On the other hand, if the ambient temperature in the vicinity of the heating device 10 is far lower, it will cause the fusion gum of the inner surface of the laminating plastic film 21 unable to melt and thus the laminating plastic film 21 cannot adhere to the article desired for lamination.
In addition, the conventional heating device 10 is constructed by several elements, which is not only complicate in assembly and occupies much space, but also increases the manufacturing costs and the assembling labor. As a result of the above-mentioned drawbacks, there is a need for an innovative heating mechanism of a laminating machine to simplify the process of manufacture, to shorten the preheating time required for lamination, and further to provide excellent lamination quality.
The primary objective of the present invention is to provide a roller heating system for a laminating machine and a process for producing the thereof, which system can heat a laminating plastic film and simultaneously compress the laminating plastic film so that the temperature of the laminating plastic film is well-controlled to ensure a good lamination quality of an article.
Another objective of the present invention is to provide a roller heating system for a laminating machine and a process for producing the thereof, wherein a heating mechanism is directly mounted on the surface of a pair of rollers so as to shorten the required preheating time of the laminating machine.
A further objective of the present invention is to provide a roller heating system for a laminating machine and a process for producing the thereof, which system combines the heating mechanism and the pair of rollers thereof so as to simplify the assemblies of the laminating machine and to diminish the integral volume thereof.
In one embodiment of this invention, the roller heating system for a laminating machine comprises a pair of rollers constructed by a first rolling shaft and a second rolling shaft, wherein the first rolling shaft and the second rolling shaft are parallel with each other. Moreover, a heating mechanism is mounted on the respective surface of the two rolling shafts, and then a heat conduction layer wraps up the respective surface of the above-mentioned rolling shafts as well as the heating mechanisms.
While the roller heating system proceeds with lamination, the heat mechanisms firstly heat the heat conduction layers on the first and second rolling shafts to a working temperature. At the same time, the first and second rolling shafts respectively rotate in a predetermined direction. An article covered with the laminating plastic films is subsequently fed into the roller heating system, and the heat conduction layers on the first and second rolling shafts heat the laminating plastic films to melt the fusion gum of the inner surfaces of the laminating plastic films. Then, the laminating plastic films with the fusion gum are forced by the compression of the first and second rolling shafts to adhere to the article desired for lamination.
Furthermore, the heating mechanism is an electric heating wire and the electric heating wire is uniformly screw wound onto the first and second rolling shafts so that the heat conduction layers can have a uniform surface temperature. Besides, in order to electrically connect the electric heating wire with a power source, an erection hole is mounted on the respective lateral end of the first and second rolling shafts and the two ends of the electric heating wires respectively penetrate through the respective erection hole and respectively connect with a respective power junction at the respective axle center of the first and second rolling shafts. Afterwards, the power junction 37 has a flexible contact with a brush and the brush is electrically connected to the power source.
The brush is constructed by a metal frame and a flexible thin metal plate. The flexible thin metal plate is mounted on the metal frame and a power joint is mounted on the metal frame and is electrically connected to the power source by a wire. The power supplied from the power source is transferred through the wire and the metal frame to the flexible thin metal plate, and then the power is transferred in a contact manner through the flexible thin metal plate to the power junction at the axle center of the rolling shaft.
In another embodiment of this invention, the first and second rolling shafts are made of metal materials, and in order to prevent short-circuiting resulted from contact of the heating mechanism (i.e. the electric heating wire) with the metal rolling shafts, an insulating layer is between the metal rolling shaft and the heating mechanism. The silicon rubber is used as the insulating layer in this embodiment.
In the roller heating system, a first driver and a second driver are respectively mounted at the ends of the first and second rolling shafts of the roller heating system, and the first driver is connected to a motor which provides the first driver with a dynamic force and the dynamic force is passed to the second driver through the first driver in such a way that the first and second rolling shafts rotate synchronously.
In addition, the first driver and the second driver are respectively a set of variable speed gears for modulating the speed and direction of rotation outputted from the motor, and the rotation direction of the first rolling shaft is opposite to that of the second rolling shaft. The first driver and the second driver are respectively mounted at the ends of the first rolling shaft and the second rolling shaft in such a way that the heat conduction layers respectively on the first and second rolling shafts interact with each other to produce a predetermined level of interferences so as to provide sufficient friction and compression to facilitate feeding and laminating the laminating plastic films.